My heater fan works on high, but not on lower speeds. Is there a separate fuse?

(Continued) mine did the same thing, and it may simply be the potentiometer on the slide switch

You may have it on the "set and forget" feature that the TC's have, you set whatever temperature you are comfortable with and forget about it, the climate control will turn on/off the A/C and or heat to maintain your desired level of comfort.When AUTO is pressed, fan speed is adjusted automatically for existing conditions. You can override fan speed at any time. To control fan speed manually, press the fan control or the steering wheel fan speed control (if equipped) to cancel automatic fan speed operation. Press the control up for higher fan speed or down for lower fan speed. Press the steering wheel control (if equipped) up for higher fan speed or down for lower fan speed. The display will show and a bar graph to indicate manual fan operation and relative speed What I did was push it all the way down until it 'clicks' then back it off just a notch off of auto

Could be the resistor/reostat, controls diff. speeds. Just changed one in chev.truck.

The resistor is in the duck work, usually on top, take out glove box.

My 1991 lincoln town car heater run on high all the time what maybe my pro8